Detect, Reject, Focus: The Role of Satiation and Odor Relevance in Cross-Modal Attention

Visual task performance has been shown to be affected differentially based on exogenous attentional demands from trigeminal odorants (Michael et al. Behav Neurosci 119:708-715, 2005). To test the exogenous influences of other biologically relevant characteristics of odorants, hungry and satiated undergraduates completed a visual search task in the presence of an odor (popcorn, jasmine, or unscented). Results showed that popcorn seemed more intense to hungry participants than those who were satiated. Reaction time results generally followed the pattern of most visual search research; significant effects were observed for feature complexity, distracter field size, and the interaction between complexity and distracter field size (Forster and Lavie J Exp Psychol 14:73-83, 2008; Itti and Koch Vision Res 40:1489-1506, 2000; Kumada Vision Res 50:1402-1413, 2010; Treisman and Gelade Cogn Psychol 12:97-136, 1980). However, olfactory group and hunger level also influenced reaction times, in that satiated participants were faster in low perceptual load (single shared feature, small set-size) conditions than hungry participants. Results suggest that olfactory attention is in a constant state of environmental monitoring for salient odors that uses resources from a shared pool. Fewer resources seem to be used when an odor with decreased saliency is detected, resulting in attentional benefits for information coming in from the visual system. These results generally support the modified Perceptual Load Theory of cross-modal attention (Tellinghuisen and Nowak Percept Psychophys 65:8717-8728, 2003) in which available shared attentional resources can be used to inhibit distracters to a visual task from other sensory modalities.